MAX3140 Maxim, MAX3140 Datasheet - Page 12

• Manufacturer Part Number: MAX3140
• Description: SPI/MICROWIRE-Compatible UART with Integrated True Fail-Safe RS-485/RS-422 Transceivers
• Manufacturer: Maxim

SPI/MICROWIRE-Compatible UART with Integrated
True Fail-Safe RS-485/RS-422 Transceivers
* In half-duplex mode, the driver outputs serve as receiver inputs. The full-duplex receiver inputs ( A and B) still have a 1/8-unit load, but
do not affect the receiver output.
12
DUPLEX
TXP
FULL
X
X
0
0
1
1
21
22
23
24
25
26
27
28
______________________________________________________________________________________
PIN
RE
DUPLEX
X
X
X
X
0
1
HALF
INPUTS
21
22
23
24
25
26
27
28
TRANSMITTING
DE
1
1
1
1
0
0
NAME
DOUT
SHDN
SCLK
RXP
V
DIN
IRQ
CS
CC
DI
X
X
1
0
1
0
RS-485 Receiver Phase. Connect RXP to GND or leave it unconnected for normal receiver
phase/polarity. Connect RXP to V
Positive Supply (4.75V to 5.25V)
UART SPI/MICROWIRE Serial-Data Input. Schmitt-trigger input.
UART SPI/MICROWIRE Serial-Data Output. High impedance when CS is high.
UART SPI/MICROWIRE Serial-Clock Input. Schmitt-trigger input.
UART Active-Low Chip-Select Input. DOUT goes high impedance when CS is high. IRQ, TX,
and RTS are always active. Schmitt-trigger input.
UART Active-Low Interrupt Output. Open-drain interrupt output to microprocessor.
UART Hardware Shutdown Input. When shut down (SHDN = 0), the UART oscillator turns off
immediately without waiting for the current transmission to end, reducing the supply current
to just leakage currents.
Shutdown (High-Z)
High-Z
Z
0
1
1
0
OUTPUTS
High-Z
Y
1
0
0
1
H/F
CC
0
0
0
0
1
1
1
1
0
1
0
1
X
X
to invert the receiver phase/polarity.
RXP
FUNCTION
0
0
1
1
0
0
1
1
0
0
1
1
X
X
Transceiver Function Tables
Pin Description (continued)
RE
0
0
0
0
0
0
0
0
0
0
0
0
1
1
INPUTS
DE
X
X
X
X
X
X
X
X
X
X
X
X
1
0
RECEIVING
≥ -0.05V
≥ -0.05V
Shorted
Shorted
≤ -0.2V
≤ -0.2V
Open/
Open/
A-B
X
X
X
X
X
X
X
X
≥ -0.05V
≥ -0.05V
Shorted
Shorted
≤ -0.2V
≤ -0.2V
Open/
Open/
Y-Z
X
X
X
X
X
X
X
X
OUTPUTS
Shutdown
(High-Z)
High-Z
RO
1
0
0
1
1
0
0
1
1
1
0
0